When you gather in chat for informal talk, anything is fair.
However, when you gather in chat for a forum member's celebration of some contest/Top 100/awards that he or she has been good enough to conduct for the board and put together for all of us, keep your comments positive and respectful. Only those few of you who have put together these projects and the chat that follows know how much work goes into the project. For the rest of us to sign into chat and post criticisms and negativity is simply not acceptable.
If, after chat, you've got comments for the thread, that's fine; but during the announcements in chat, be positive or sign out of chat please.